class Student {
    String name = "张三";
    int age;
    static String classname = "901";

    public static final Student obj = new Student();

    private Student() {}

    static void show() {
        System.out.printf("static show .... name = %s!\n", classname);
    }
}

public class staticTest {
    static public void main(String [] args) {
        Student.classname = "701";
        System.out.printf("Student.classname = %s\n", Student.classname);
        Student.show();

        Student.obj.show();

        // Student a = new Student();
        // a.show();
        // Student b = new Student();

        // System.out.printf("a.classname = %s\n", a.classname);
        // a.classname = "902";
        // System.out.printf("b.classname = %s\n", a.classname);
        // System.out.printf("Student.classname = %s\n", Student.classname);

    }
}
